1. Field
The present application relates generally to wireless communications, and more specifically to systems and methods for assisting nodes in turning on sleeping network entities.
2. Background
The 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) represents a major advance in cellular technology and is the next step forward in cellular 3G services as a natural evolution of Global System for Mobile communications (GSM) and Universal Mobile Telecommunications System (UMTS). LTE provides for an uplink speed of up to 50 megabits per second (Mbps) and a downlink speed of up to 100 Mbps and brings many technical benefits to cellular networks. LTE is designed to meet carrier needs for high-speed data and media transport as well as high-capacity voice support. Bandwidth is scalable from 1.25 MHz to 20 MHz. This suits the needs of different network operators that have different bandwidth allocations, and also allows operators to provide different services based on spectrum. LTE is also expected to improve spectral efficiency in 3G networks, allowing carriers to provide more data and voice services over a given bandwidth. LTE encompasses high-speed data, multimedia unicast and multimedia broadcast services.
The LTE physical layer (PHY) is a highly efficient means of conveying both data and control information between an evolved NodeB (eNB) and mobile entities (MEs), such as, for example, access terminals (ATs) or user equipment (UE). The LTE PHY employs some advanced technologies that are new to cellular applications. These include Orthogonal Frequency Division Multiplexing (OFDM) and Multiple Input Multiple Output (MIMO) data transmission. In addition, the LTE PHY uses Orthogonal Frequency Division Multiple Access (OFDMA) on the downlink (DL) and Single-Carrier Frequency Division Multiple Access (SC-FDMA) on the uplink (UL). OFDMA allows data to be directed to or from multiple users on a subcarrier-by-subcarrier basis for a specified number of symbol periods.
Advanced cellular networks, such as LTE networks, may be being deployed for data-intensive applications to be performed by MEs. LTE networks, which include LTE cells that wirelessly communicate with the MEs, may consume a significant amount of power, which is wasteful if no ME is utilizing the fourth generation (4G) services provided by the LTE cells.
In a wireless communication network, ones of network entities (e.g., eNBs) controlling these LTE cells may be in an OFF or sleep state to conserve power, such as when these network entities are not needed to service the MEs. For example, eNBs in the OFF/sleep state may provide wireless service to the MEs, whereas eNBs that are powered down state may maintain communication capability between hotspot cells and the coverage cells without providing wireless service to the MEs. Transitioning to a powered OFF/sleep state therefore may not entail powering every component of the eNB hotspot cell entirely off, although mobile service components of the eNB hotspot cell may be generally powered OFF.
In some scenarios, the MEs that could be served by the network entities in the OFF or sleep could be supported by supported by neighboring cells. At times, networking entities controlling the neighboring cells may might detect a high load on a given eNB and attempt to offload one or more MEs that the given eNB is servicing to a network entity in the sleep state. In this context, there is a need to efficiently identify which sleeping eNBs to awake for the purpose of offloading one or more MEs from the given eNB to neighboring cells.